public static KeyframeTrack FromMatrices(IList <Single> times, IEnumerable <Matrix4> transforms)
{
var track = new KeyframeTrack();
var translations = transforms.Select(m => m.ExtractTranslation()).ToList();
var rotations = transforms.Select(m => m.ExtractRotation()).ToList();
var scales = transforms.Select(m => m.ExtractScale()).ToList();
// Quaternion sign fixup
// The same rotation can be represented by both q and -q. However the Slerp path
// will be different; one will go the long away around, the other the short away around.
// Replace quaterions to ensure that Slerp will take the short path.
float flip = 1.0f;
for (var i = 0; i < rotations.Count - 1; i++)
{
var r0 = rotations[i];
var r1 = rotations[i + 1];
var dot = QuatHelpers.Dot(r0, r1 * flip);
if (dot < 0.0f)
{
flip = -flip;
}
rotations[i + 1] *= flip;
}
for (var i = 0; i < times.Count; i++)
{
track.AddTranslation(times[i], translations[i]);
track.AddRotation(times[i], rotations[i]);
var scaleShear = new Matrix3(
scales[i][0], 0.0f, 0.0f,
0.0f, scales[i][1], 0.0f,
0.0f, 0.0f, scales[i][2]
);
track.AddScaleShear(times[i], scaleShear);
}
return(track);
}
public static KeyframeTrack FromMatrices(IList <Single> times, IEnumerable <Matrix4> transforms)
{
var track = new KeyframeTrack();
var translations = transforms.Select(m => m.ExtractTranslation()).ToList();
var rotations = transforms.Select(m => m.ExtractRotation()).ToList();
var scales = transforms.Select(m => m.ExtractScale()).ToList();
// Quaternion sign fixup
// The same rotation can be represented by both q and -q. However the Slerp path
// will be different; one will go the long away around, the other the short away around.
// Replace quaterions to ensure that Slerp will take the short path.
for (var i = 1; i < rotations.Count; i++)
{
var r0 = rotations[i - 1];
var r1 = rotations[i];
var dot = Vector3.Dot(r0.Xyz, r1.Xyz);
var ang = Math.Acos(dot);
if (dot < -0.0001f)
{
rotations[i] = new Quaternion(-r1.X, -r1.Y, -r1.Z, -r1.W);
}
}
for (var i = 0; i < times.Count; i++)
{
track.AddTranslation(times[i], translations[i]);
track.AddRotation(times[i], rotations[i]);
var scaleShear = new Matrix3(
scales[i][0], 0.0f, 0.0f,
0.0f, scales[i][1], 0.0f,
0.0f, 0.0f, scales[i][2]
);
track.AddScaleShear(times[i], scaleShear);
}
return(track);
}